March 2019 - Page 810 of 895 -

The thermal efficiency of a reversible heat engine operating between two given thermal reservoirs is 0.4. The device is used either as a refrigerator or as a heat pump between the same reservoirs. Then the coefficient of performance as a refrigerator (COP)R and the co-efficient of performance as a heat pump (COP)HP are _______________?

The thermal efficiency of a reversible heat engine operating between two given thermal reservoirs is 0.4. The device is used either as a refrigerator or as a heat pump between the same reservoirs. Then the coefficient of performance as a refrigerator (COP)R and the co-efficient of performance as a heat pump (COP)HP are _______________?

A. (COP)R = (COP)HP = 0.6
B. (COP)R = 2.5; (COP)HP = 1.5
C. (COP)R = 1.5; (COP)HP = 2.5
D. (COP)R = (COP)HP = 2.5

Chemical Heat Transfer

Heat transfer rate per unit area is called_________________?

Chemical Heat Transfer / admin

Heat transfer rate per unit area is called_________________?

A. Thermal conductivity
B. Heat flux
C. Heat transfer co-efficient
D. Thermal diffusivity

Heat transfer rate per unit area is called_________________? Read More »

Chemical Heat Transfer

Tube pitch is the _______________ of tube diameters and the clearances?

Chemical Heat Transfer / admin

Tube pitch is the _______________ of tube diameters and the clearances?

A. Sum
B. Difference
C. Ratio
D. None of these

Tube pitch is the _______________ of tube diameters and the clearances? Read More »

Chemical Heat Transfer

A black body when hot, emits heat radiation of _____________ wavelengths?

Chemical Heat Transfer / admin

A black body when hot, emits heat radiation of _____________ wavelengths?

A. Small
B. Large
C. All
D. One fixed

A black body when hot, emits heat radiation of _____________ wavelengths? Read More »

Chemical Heat Transfer

With increase in temperature, the thermal conductivity of non-metallic amorphous solids_________________?

Chemical Heat Transfer / admin

With increase in temperature, the thermal conductivity of non-metallic amorphous solids_________________?

A. Decreases
B. Increases
C. Remain constant
D. First decreases upto certain temperature and then increases

With increase in temperature, the thermal conductivity of non-metallic amorphous solids_________________? Read More »

Chemical Heat Transfer

Which of the following parameters is increased by use of finned tube in a multipass shell and tube heat exchanger ?

Chemical Heat Transfer / admin

Which of the following parameters is increased by use of finned tube in a multipass shell and tube heat exchanger ?

A. Tube side pressure drop and the heat transfer rate
B. Convective heat transfer co-efficient
C. Effective tube surface area for convective heat transfer
D. All A. B. and C.

Which of the following parameters is increased by use of finned tube in a multipass shell and tube heat exchanger ? Read More »

Chemical Heat Transfer

Value of Nusselt number [Nu = (hD/k)] for the heat transfer by conduction from a droplet or a spherical particle to a surrounding stagnant film is__________________?

Chemical Heat Transfer / admin

Value of Nusselt number [Nu = (hD/k)] for the heat transfer by conduction from a droplet or a spherical particle to a surrounding stagnant film is__________________?

A. 0.5
B. 2
C. 10
D. 100

Value of Nusselt number [Nu = (hD/k)] for the heat transfer by conduction from a droplet or a spherical particle to a surrounding stagnant film is__________________? Read More »

Chemical Heat Transfer

The main purpose of providing fins on heat transfer surface is to increase the_________________?

Chemical Heat Transfer / admin

The main purpose of providing fins on heat transfer surface is to increase the_________________?

A. Temperature gradient
B. Mechanical strength of the equipment
C. Heat transfer area
D. Heat transfer co-efficient

The main purpose of providing fins on heat transfer surface is to increase the_________________? Read More »

Chemical Heat Transfer

When vaporisation takes place through a blanketting film of gas, the phenomenon is termed as ___________________ boiling?

Chemical Heat Transfer / admin

When vaporisation takes place through a blanketting film of gas, the phenomenon is termed as ___________________ boiling?

A. Pool
B. Nucleate
C. Transition
D. Film

When vaporisation takes place through a blanketting film of gas, the phenomenon is termed as ___________________ boiling? Read More »

Chemical Heat Transfer

Agitated film evaporator is suitable for concentrating _____________ liquids?

Chemical Heat Transfer / admin

Agitated film evaporator is suitable for concentrating _____________ liquids?

A. Foaming
B. Viscous
C. Very thin
D. Corrosive

Agitated film evaporator is suitable for concentrating _____________ liquids? Read More »

Chemical Heat Transfer